Improvement in the manufacture of paper-pulp from wood



UNITED STATES PATENT OFFICE. I

STEPHEN M. ALLEN, OF DUXBURY, MASSACHUSETTS.

IMPROVEMENT IN THE MANUFACTURE OF PAPER-PULP FROM WOOD.

Specification forming part of Letters Patent No. 212,782, dated March 4,1879 application filed May 1, 1878.

To all whom it may concern:

Be it known that I, STEPHEN M. ALLEN, of Duxbury, in the county ofPlymouth and State of Massachusetts, have invented anew and usefulImprovement in the Manufacture of Paper-Pulp from Wood, which improvement is fully set forth in the following specification.

This invention has for its object certain improvements which I have madeupon my original wood-pulping process and pulp for paper and otherpurposes, as described 'in my patent of March 21, 1863, No. 38,620.

. The filaments of wood are so tenaciously intwined and set togetherthat I have found in fibrilizing the same for fine papers, where it isindispensable to preserve a good length as well as to produce finenessin the fibril, that a stripping and crushing process could be used withadvantage in preparing the wood for ultimate crushing and grinding. Asteep ing in acid or alkaline solutions is also employed when deemeddesirable.

1 secure a good length to the fiber, which is well maintained bystripping the same longitudinally, an d by the crushing down wardprocess which upsets the fiber, so to speak, or sets it downagainstitself, thereby making it more porous or spongy without breakingor severing the thread of the same.

The effect of this mechanical treatment or longitudinal stripping andcrushing of the fiber from the wood is, that it materially aids anysubsequent chemical treatment, enabling the latter to be accomplishedwith less strength ofsolution, while the subsequent crushing andgrinding to complete the pulping process is thereby rendered mucheasier, from the fact that the filaments are softer, and consequentlythey come out of the machine larger and finer than they couldotherwisebe manufactured.

The following description will enable those skilled in the art to whichit appertains to make and use my invention.

I take nearly all the varieties of wood, such as cottonwood,bass-wood,poplar, pine, spruce, maple, birch, beech, hemlock, and cedar, and cutor saw the logs into suitable size for the machine used in reducing thesame ready for crushing, and strip or fibrilize the same by means ofmachinery so arranged as to tear the fiber in its longitudinal directionin small filaments.

The teeth or spurs of the crushing or strip ping machine are usually ofabout one-eighth of an inch in diameter, moving by feed-rollers againstthe sides or face of the stick of wood, and tearing andcrushing itdownward along lines of the annual deposits or growth of the fiber,upsetting though not cutting the same across their axes, and making thefilaments more spongy.

This stripping and crushing process may be done in various ways. Anendless belt armed with spurs or teeth and sustained in contact with thewood by rollers behind might be used, suitable mechanism for feeding thewood to the belt being employed. Instead of a belt, plates moving inright lines in contact with the wood, or even cylinders of properdiameter, might be used. Other means might also be employed. The effectis not only to preserve the fiber in good length for paperpulp, but toopen the filaments or separate the small fibrils one from the other, sothat future grinding or treatment by alkaline solutions will leave themmuch finer as well as longer than when torn by transversely-crushin grollers from the solid stick or bolt of wood.

The alkaline or acid solutions permeating more thoroughly and dissolvingthe albuminous or starchy matter therein more easily than before, thefiber is more readily crushed and pulped. the stock, I usually treat thesame with warm water, or acid or alkaline solutions, and sometimes withbleaching liquors.

The composition of such solutions and the mode of application of themneed not be here more fully set forth, as such treatment of fiber iswell known in the art, and does not by itself, but only in connectionwith other steps in the treatment, form a part of this inven tion.

After this chemical treatment I compress the fibers in bundles, andcrush or grind the same by friction against revolving metal, stone, orcomposition rollers, properly dressed on their surface, preferably asshown in my patent of March 12, 1878, and thus reducing the same to afine pulp, to be used pure or mixed with other pulped fibers. Isometimes After thus stripping the fiber from i crush or grind thestripped filaments without the steeping process, according to thequality of pulp desired.

The action and result of the process of longitudinally crushing down andstripping off the fiber as above explained is essentially different fromgrinding off the fiber by forcing the stick of wood endwise betweenstones rotating in the same or opposite directions toward or away fromthe wood, or from any known process of separating the fibers from wood.The fiber and the pulp and paper prepared therefrom are superior to pulpand paper of wood fiber heretofore made in the softness, fineness, andgood length of the filaments.

Having thus described my wood-pulping process, which is an improvementupon my original pulping process as described in my patent before named,what I now claim, and desire to secure by Letters Patent, is-

1. The method of preparing fiber, the same consisting in separating thefibers or filaments from a block or stick of wood by crushing down orupsetting them, and stripping or tearing them off in a directionlengthwise of the stick of wood, substantially as described. I

2. The method of preparing and treating fiber, the same consisting incrushing down and stripping the filaments longitudinally from a block orstick of wood, and in crushing and grinding said longitudinallyrstrippedfilaments, substantially as set forth.

3. The process of preparing wood fiber for pulp, the same consisting insuccessive operations of longitudinally stripping or crushing thefilaments off the blocks or sticks of wood, crushing or grinding thesame by means of rollers, and the treatment of the same in acid oralkaline solutions, in combination, substantially as and for thepurposes before named.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

STEPHEN M. ALLEN.

WVitnesses WALTER J ONES, Gno. A. SAVAGE.

